This invention relates to a method for inhibiting corrosion of a metal surface, to a method for pretreating a metal surface to improve the adhesion of paint thereto and to a method for painting a metal surface.
Corrosion of metal surfaces is a long-recognized problem to which many solutions have been proposed. Among others, various amines have been proposed as corrosion inhibitors. Of course, not all amines function as corrosion inhibitors and selection of an appropriate amine to function in a given environment continues to present difficulties. The present invention provides a new class of amines which are useful as corrosion inhibitors.
One means of minimizing the impact of corrosion on metal surfaces has been to coat the surface with paint. The paint acts as a barrier between the metal surface and the environment and thus helps to prevent or at least minimize corrosion of the metal surface. However, one problem associated with this solution is that paint does not always adhere properly to the metal surface. The result may be peeling, cracking, blistering, or flaking of the paint, thus rendering the substrate metal surface again subject to corrosion.
To alleviate the problem of poor adhesion of paint to metal surfaces one solution has been to subject the metal substrate to a treatment which is known as phosphatizing. Such a treatment typically assists in rendering the metal surface less subject to corrosive attack and at the same time rendering the surface more suitable for application of paint. The resulting bond between the metal surface and the paint is thus greatly improved.
The phosphatizing process thus provides one means for inhibiting corrosion of a metal surface as well as a means for promoting adhesion of paint to a metal surface. However, phosphatizing baths require that precise formulations be maintained and processing procedures and conditions of operations must be controlled within narrow limits. The phosphatizing process also requires that the metal surface be given two rinses subsequent to the phosphatizing bath, one a water rinse and the final rinse in a passivating solution.
A need thus exists for a simple means to achieve results similar to that obtained with a phosphatizing process, but without the complexity of such a treatment.